WO2012128729A1 - Tube à décharge de gaz ayant un corps métallique pour des pointes de courant élevées - Google Patents

Tube à décharge de gaz ayant un corps métallique pour des pointes de courant élevées Download PDF

Info

Publication number
WO2012128729A1
WO2012128729A1 PCT/SI2012/000016 SI2012000016W WO2012128729A1 WO 2012128729 A1 WO2012128729 A1 WO 2012128729A1 SI 2012000016 W SI2012000016 W SI 2012000016W WO 2012128729 A1 WO2012128729 A1 WO 2012128729A1
Authority
WO
WIPO (PCT)
Prior art keywords
insulating element
discharge tube
gas discharge
graphite
metal body
Prior art date
Application number
PCT/SI2012/000016
Other languages
English (en)
Inventor
Robert ROZMAN
Original Assignee
Iskra Zascite D.O.O.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Iskra Zascite D.O.O. filed Critical Iskra Zascite D.O.O.
Publication of WO2012128729A1 publication Critical patent/WO2012128729A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T4/00—Overvoltage arresters using spark gaps
    • H01T4/10—Overvoltage arresters using spark gaps having a single gap or a plurality of gaps in parallel
    • H01T4/12—Overvoltage arresters using spark gaps having a single gap or a plurality of gaps in parallel hermetically sealed
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T1/00—Details of spark gaps
    • H01T1/20—Means for starting arc or facilitating ignition of spark gap
    • H01T1/22—Means for starting arc or facilitating ignition of spark gap by the shape or the composition of the electrodes

Definitions

  • the invention refers to gas discharge tubes with a metal body used for overvoltage protection, where discharge tubes are needed for highest current pulses.
  • the technical problem is a constructional solution to a gas discharge tube configured on a metal body and having a function of an external electrode in combination with a protecting element for graphite coatings, which must be shaped in a way to allow optimum reaction of a gas discharge tube in case of an excess voltage increase.
  • the shape of a protecting element must be such to provide protection of an insulating element in case of arc formation in the interior of the gas discharge tube against material vapours, preferably copper, of which the body and the external electrode are made of. Heating induced by arc burn causes a relatively rapid melting and evaporation of copper, which may cause severe thermal damages on the external electrode in the interior of the gas discharge tube.
  • the evaporated material may cause formation of a thin conductive layer on insulating elements, which results in reduced ohmic resistance between the two electrodes. All that can have influence on the change of ignition voltages and consequently on the applicability of a gas discharge tube.
  • a shield of materials In order to improve high-temperature resistance of the interior of the external electrode, a shield of materials must be produced, which have good resistance to high temperatures and are good electric current conductors. Typical materials are molybdenum and tungsten-copper, where the share of tungsten is at least 10 %.
  • the shield must cover at least the most heavily burdened parts of the external electrode, i. e.
  • the central electrode which preferably also consists of high-temperature resistant materials (molybdenum or tungsten-copper).
  • the electrodes are separated by an insulating element preferably of ceramics or a material having similar chemical properties.
  • Graphite paths should be applied on one or both insulating elements, wherein the shape of graphite paths should be such to allow an adequately rapid reaction of the gas discharge tube to increasing overvoltage. This is important especially in case of a rapid increase in voltage, which is normally of an order of magnitude of 10 9 V/s or more.
  • the speed of reaction of a gas discharge tube defines a dynamic ignition voltage, which is always higher than the ignition voltage in case of a slow increase in voltage (e. g. 100 V/s).
  • the task and goal of the invention are thus a constructional shape of insulating elements in combination with the shape of graphite paths.
  • Gas discharge tubes for highest current pulses are used in overvoltage protections of class I and II. They are predominantly used in installation systems of TT and TN type.
  • a gas discharge tube includes two electrodes separated by an insulator and a hermetically closed space, which is filled with a mixture of gases. A distance between the electrodes and the mixture of gases define both the ignition voltage and discharge current capacities.
  • the element In case of low voltage on the electrodes of a gas discharge tube the element is a perfect insulator. When the voltage increases above a certain limit, a breakdown between the electrodes in the gas appears and a conductive arc is created. Short-term current loads can amount even to 200 kA. After the breakdown is over, the arc needs to be extinguished in the presence of the resulting current, which may be up to 100 A.
  • Patent US 4,924,347 discloses gas lightning arresters with a ceramic body and gas lightning arresters with a metal body.
  • gas lightning arresters with a ceramic body are much more frequently used in practice, where the electrodes are separated by a ceramic insulating element usually in the form of a tube.
  • the openings of a ceramic tube are closed by metal elements or by an assembly of metal elements functioning as electrodes.
  • Arresters with a metal body are relatively rare. They have a metal body in the form of a tube having an opening only at one end and functioning as an external electrode. The opening is closed by an insulating element, through which a second electrode protrudes.
  • its major drawback was a use of a glass insulating element, which proves inappropriate especially in mechanical and temperature loads.
  • Patent SI 23042 discloses a new solution to a gas discharge tube with a metal body, which has a ceramic insulating element instead of a glass one. This solves the problems of mechanical and temperature resistance of gas discharge tubes with a metal body.
  • the main advantage of variants with a metal body is a larger surface of internal electrodes compared to an equally sized variant with a ceramic body. Larger surfaces of electrodes provide for smaller loads of electrodes and thus for a better endurance of a gas discharge tube in case of high-current surges.
  • a problem that may remain is only a considerably shorter external distance between the electrodes in a discharge tube with a metal body in comparison with the one with a ceramic body, which is evident also from the figures of patent US 4,924,347. A shorter distance increases a possibility of an external breakdown.
  • Patents CA 1 ,126,329 and US 6,617,770 disclose several solutions of applying graphite paths on an insulating element. The graphite coating in all the mentioned cases is added onto an insulating element of a gas discharge tube with a ceramic body.
  • Patent SI 23042 discloses a solution to a gas discharge tube with a metal body and a coating of graphite paths. A precise form of the coating is not defined. Description of a Solution to the Technical Problem
  • a gas discharge tube with a metal body comprises a metal body as an external electrode, a central electrode, a shield of the external electrode on the most heavily loaded place, insulating element, gas filling and graphite paths on the insulating elements.
  • a quick reaction time and reliable operation during and after high-current loads of the discharge tube is provided for by the shield, a typical geometrical shape of the insulating elements as well as by adequately shaped coatings of graphite paths on the insulating elements in combination with high-temperature resistant materials.
  • Figure 6 Presentation of a shape of the graphite coating on an insulating element, where the coating is not in contact with electrodes
  • Figure 7 Presentation of a shape of the graphite coating on an insulating element, where the coating is in contact with electrodes
  • Figure 8 Presentation of protection of insulating elements prior to metal vapour deposition.
  • a gas discharge tube with a metal body for high-current surges of the invention consists of an external body 1 that is simultaneously an external electrode consisting of a narrow part 1a and a wide hollow cylindrical part 1b.
  • a cylindrical shield 2 which houses about one third of an internal part 3 of a central electrode.
  • a narrower external part 4 of the central electrode protrudes through an insulating element 5 and an insulating element 6.
  • the insulating element 5 and/or 6 is provided with a coating of graphite conductive paths 8 having a thickness only about one micrometre or less. As shown in Figure 6, the graphite path 8 is shaped like a capital letter J.
  • the interior of the discharge tube is filled with a suitable mixture 7 of gases.
  • the metal body 1 is preferably of copper, which does not have the optimum resistance against high temperatures produced during arc burn in the interior of the gas discharge tube.
  • High-temperature resistance of the interior of the external electrode is enhanced by the shield 2 made of materials having good resistance against high temperatures and being additionally good conductors. Molybdenum or tungsten-copper, wherein the share of tungsten is at least 10 %, are used in embodiments.
  • the shield 2 has a shape of a short cylindrical vessel covering the external electrode 1 in the area of the peak of the internal part 3 of the central electrode, where said most heavily loaded external part of the electrode lies (see Figure 1). The entire external electrode could after all be made of a high-temperature resistant material; however, such solution is not economically justified.
  • the internal part 3 of the central electrode is made of high- temperature resistant materials such as molybdenum or tungsten-copper, where the share of tungsten is at least 10 %.
  • high- temperature resistant materials such as molybdenum or tungsten-copper, where the share of tungsten is at least 10 %.
  • Such combination of materials is needed because the active surface of the central electrode is considerably smaller than the surface of the external electrode.
  • the central electrode can be of two parts for economic reasons, where the external part 4 is made of copper that is cheaper.
  • Both the insulating element 5 and the insulating element 6 are of ceramic or of a material having similar chemical properties.
  • Graphite paths 8 may be applied onto each of the insulating elements 5 and/or 6.
  • the function of a graphite coating is well known, as it has influence especially on the reaction time of a gas discharge tube to increasing overvoltage. This is of importance especially in case of a rapid increase in voltage, which is normally of an order of magnitude of 10 9 V/s or more.
  • the speed of reaction of the gas discharge tube defines the dynamic ignition voltage, which is always higher than the ignition voltage in case of a slow increase in voltage, e. g, 100 V/s.
  • a specially shaped coating of graphite paths 8 on the insulating element 5 and/or 6 reduces the dynamical ignition voltage. This increases the protection level of overvoltage protection, as the highest possible voltage on the gas discharge tube with quick reaction is lower than in case of a gas discharge tube with slow reaction.
  • the graphite paths of the invention are made in a way that the shape of the insulating elements provides for the protection of paths against arc.
  • a special shape of the insulating element 5 and/or the insulating element 6 prevents the graphite coating from getting in contact with too hot plasma produced during arc burn.
  • the arc has certain electric resistance and gets heated due to electric current flowing through the arc. Due to heat conduction also the rest of the gas around the arc gets heated and consequently starts conducting electric current as well. Between the electrodes in the gas discharge tube there is hot plasma, the temperature distribution of which depends on the electric current heating the plasma or the mixture 7 of gases.
  • the temperature increases more rapidly on the parts where more current flows. It is the basic property of the current to choose a path with smallest resistance, which means that the area of the graphite coating can be protected by a suitable barrier in order to prevent the arc from running closely to the graphite coating. Consequently, a lower temperature is anticipated in the area of the graphite coating and thus a smaller influence of the hot plasma on the graphite coating.
  • FIG. 2 shows an example of use of the insulating element 5 and the insulating element 6, where the graphite coating is applied onto the insulating element 5.
  • the insulating element 6 is shaped like a plate with a hole and the plate does not extend to the external electrode 1.
  • Shading can also be provided for without the insulating element 6.
  • a gas discharge tube with a metal body as shown in Figure 3 according to Variant I is typical for the shape of its insulating element 5a, which has a narrow higher section 5a' over the entire circumference and a graphite path 8a is arranged over a surface 5a".
  • a gas discharge tube with a metal body as shown in Figure 4 according to Variant II is typical for the shape of its insulating element 5b, which has a narrow section 5b' over the entire circumference and a graphite path 8b is arranged over a surface 5b".
  • a gas discharge tube with a metal body as shown in Figure 5 according to Variant III is typical for the shape of its insulating element 5c, which has a recess 5c' over the entire circumference and a graphite coating 8c is arranged within said recess.
  • the shape of the coating of graphite paths 8 not only provides for the endurance of the graphite coating but also has influence on ignition voltages.
  • a distance of the graphite coating from the electrodes influences not only the ignition voltage but also the stability of the ignition voltage in consecutive measurements.
  • the distance between the electrodes on the insulating element of the gas discharge tube with a metal body is considerably shorter than in case of an equally sized gas discharge tube with a ceramic body, so a precise application of graphite paths onto a surface is of utter importance.
  • Figures 6 and 7 show the basic characteristics of the shape of application of graphite paths 8 on the insulating element 5.
  • Figures 6 and 7 show a cross-section of a gas discharge tube directly above the insulating element 5 viewed in direction towards the insulating element 5, where various examples of application of graphite paths are shown.
  • a part of the application of the graphite paths being closest to the central electrode must be applied in tangential direction with respect to the contact point of the external part 4 of the central electrode with the primary insulating element 5 ( Figure 6). The most equal distance is thus achieved between the central electrode and the beginning of application of graphite paths.
  • the dotted line in Figure 6 shows the suitable tangent line, which is spaced by a distance 1c from the contact point of the central electrode and the insulating element.
  • one portion of the coating of the graphite paths 8 closest to the external electrode must be applied onto a portion of or the entire circular line, which has the same centre as the circular line delimiting a contact point of the external electrode 1 with the insulating element 5.
  • An equal distance between the external electrode and the beginning of coating of the graphite paths 8 is herewith achieved.
  • a dotted circular line represents also a corresponding concentric circular line, which is one distance 1d away from the contact of the external electrode and the insulating element.
  • the stability of ignition voltages in consecutive measurements of ignition voltages can also be improved in that the coating of the graphite paths 8 is in contact either with the central or the external electrode.
  • a graphite path 8e is shaped approximately like a capital letter J and is in contact with the central electrode.
  • a graphite path 8f is shaped like a small letter r and is in contact with the external electrode.
  • a graphite path 8g is shaped like a short line and is in contact with the external electrode.
  • the properties of the coating of the graphite paths 8 on the insulating element 5, as shown in Figures 6 and 7, are generally valid also for the coatings of the graphite paths 8 on the insulating element 6.
  • the spot onto which a graphite path is applied depends on the requirements and geometry of the gas discharge tube. The coating may be applied onto the insulating element 5 or 6 or even on both insulating elements.
  • the circle B marks a portion shielded with the insulating element 6, where vapour deposition is minimal.
  • the described innovation contributes to high ohmic resistance between the electrodes of the gas discharge tube even in case of high-current surges, which cause evaporation of material from the metal electrodes.
  • the reaction time of the gas discharge tube is of an order of several tens of nanoseconds. If the voltage on the electrodes increases very rapidly, the voltage can reach a very high value. Consequently a breakdown may occur between the narrow external part 4 of the central electrode and the external electrode 1 on the external part of the discharge tube.
  • An efficient and a simple solution is an additional ring 5' configured on the external part of the primary insulating element 5. Said ring 5' extends the external insulation distance between the electrodes of the gas discharge tube. This distance is considerably longer than the distance between the electrodes in the interior of the gas discharge tube. A possibility of external breakdown is herewith strongly reduced and the installation of the gas discharge tube simplified.
  • the gas discharge tube with a metal body for high-current surges of the invention solves a problem of protection of graphite conductive paths and consequently contributes to a more reliable reaction of the discharge tube. Since the function of shading the arc is provided for, the life span of the graphite coating is extended, which results in a better endurance of the gas discharge tube.
  • the stability of ignition voltages of the gas discharge tube is improved if the graphite paths are applied in a way that they are in contact with the metal body.
  • the shield made of a high- temperature resistant material reduces evaporation of material from the metal body. All these new technological approaches make it possible to manufacture gas discharge tubes for current surges of up to 200 kA, wherein the external dimensions of the gas discharge tube are smaller than those of the currently known solutions.

Landscapes

  • Thermistors And Varistors (AREA)

Abstract

L'invention concerne des tubes à décharge de gaz ayant un corps métallique utilisé pour une protection contre les surtensions, les tubes à décharge étant nécessaires pour les impulsions de courant les plus élevées. L'invention concerne un tube à décharge de gaz ayant un corps métallique pour des pointes de courant élevées, consistant en : un corps externe (1) qui est simultanément une électrode externe, une électrode centrale constituée d'une partie interne (3) et d'une partie externe (4), un élément d'isolation (5), un élément d'isolation (6), des trajets de graphite (8) et un mélange (7) de gaz dans l'intérieur du tube de décharge, où, dans l'intérieur d'une partie (1b) du corps (1), il est disposé un bouclier cylindrique (2) qui reçoit environ un tiers de la partie interne (3) de l'électrode centrale. Une partie externe plus étroite (4) de l'électrode centrale fait saillie à travers l'élément d'isolation (5) et l'élément d'isolation (6), l'élément d'isolation (5 et/ou 6) étant doté d'un revêtement de trajets conducteurs de graphite (8) ayant une épaisseur seulement d'environ un micromètre ou moins. Le trajet de graphite (8) est formé approximativement comme une lettre majuscule J et est disposé sur l'élément d'isolation (5). L'élément d'isolation (6) est façonné comme une plaque ayant un trou, la plaque ne s'étendant pas jusqu'à l'électrode externe (1). La fonction de bouclier de l'arc est ainsi fournie afin de protéger le revêtement de graphite sur l'élément d'isolation (5).
PCT/SI2012/000016 2011-03-21 2012-03-16 Tube à décharge de gaz ayant un corps métallique pour des pointes de courant élevées WO2012128729A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SIP-201100094 2011-03-21
SI201100094A SI23691A (sl) 2011-03-21 2011-03-21 Plinski odvodnik s kovinskim ohišjem za visokotokovne udare

Publications (1)

Publication Number Publication Date
WO2012128729A1 true WO2012128729A1 (fr) 2012-09-27

Family

ID=46208148

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SI2012/000016 WO2012128729A1 (fr) 2011-03-21 2012-03-16 Tube à décharge de gaz ayant un corps métallique pour des pointes de courant élevées

Country Status (2)

Country Link
SI (1) SI23691A (fr)
WO (1) WO2012128729A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102017115030A1 (de) * 2017-07-05 2019-01-10 Tdk Electronics Ag Ableiter zum Schutz vor Überspannungen
CN113765083A (zh) * 2021-07-22 2021-12-07 西安交通大学 一种基于石墨-金属镀层的具有高可焊性的可控多层间隙过电压保护器

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1126329A (fr) 1978-08-03 1982-06-22 Axel Hahndorff Tube a decharge dans un gaz, plus particulierement du type limiteur de surtensions
US4924347A (en) 1988-09-08 1990-05-08 Compagnie Industrielle De Tubes Et Lampes Electriques Citel Gas lightning arrester containing a mineral addition agent
US5995355A (en) 1996-01-12 1999-11-30 Siemens Ag Gas-filled discharge path in a form of a spark gap or an overvoltage diverter
US6617770B2 (en) 2001-03-09 2003-09-09 Shinko Electric Industries Co., Ltd Gas filled switching electric discharge tube
US20080218082A1 (en) * 2005-08-02 2008-09-11 Epcos Ag Spark-Discharge Gap
US7795810B2 (en) 2005-03-23 2010-09-14 Epcos Ag Gas-filled discharge gap
SI23042A (sl) 2009-04-24 2010-10-29 Iskra Zaščite d.o.o. Plinski odvodnik s kovinskim ohiĺ jem in z nanosom prevodne plasti na izolativnem elementu

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1126329A (fr) 1978-08-03 1982-06-22 Axel Hahndorff Tube a decharge dans un gaz, plus particulierement du type limiteur de surtensions
US4924347A (en) 1988-09-08 1990-05-08 Compagnie Industrielle De Tubes Et Lampes Electriques Citel Gas lightning arrester containing a mineral addition agent
US5995355A (en) 1996-01-12 1999-11-30 Siemens Ag Gas-filled discharge path in a form of a spark gap or an overvoltage diverter
US6617770B2 (en) 2001-03-09 2003-09-09 Shinko Electric Industries Co., Ltd Gas filled switching electric discharge tube
US7795810B2 (en) 2005-03-23 2010-09-14 Epcos Ag Gas-filled discharge gap
US20080218082A1 (en) * 2005-08-02 2008-09-11 Epcos Ag Spark-Discharge Gap
SI23042A (sl) 2009-04-24 2010-10-29 Iskra Zaščite d.o.o. Plinski odvodnik s kovinskim ohiĺ jem in z nanosom prevodne plasti na izolativnem elementu

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DATABASE EPODOC [online] EUROPEAN PATENT OFFICE, THE HAGUE, NL; 29 October 2010 (2010-10-29), Database accession no. SI-200900120-A *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102017115030A1 (de) * 2017-07-05 2019-01-10 Tdk Electronics Ag Ableiter zum Schutz vor Überspannungen
CN110800176A (zh) * 2017-07-05 2020-02-14 Tdk电子股份有限公司 用于过电压防护的放电器
US11025037B2 (en) 2017-07-05 2021-06-01 Tdk Electronics Ag Arrester for protection against overvoltages
CN110800176B (zh) * 2017-07-05 2021-10-01 Tdk电子股份有限公司 用于过电压防护的放电器
CN113765083A (zh) * 2021-07-22 2021-12-07 西安交通大学 一种基于石墨-金属镀层的具有高可焊性的可控多层间隙过电压保护器

Also Published As

Publication number Publication date
SI23691A (sl) 2012-09-28

Similar Documents

Publication Publication Date Title
US6710996B2 (en) Surge arrestor
ES2819508T3 (es) Dispositivo de conmutación eléctrica para aplicaciones de media y/o alta tensión
US7932673B2 (en) Gas discharge tube
US4769736A (en) Gas discharge surge arrester
US6788519B2 (en) Pressure-resistant encapsulated air-gap arrangement for the draining off of damaging perturbances due to overvoltages
US4493004A (en) Surge arrester with a gas-filled housing
US7595461B2 (en) Heavy-duty circuit breaker with erosion-resistant short-circuit current routing
US4345293A (en) Arrester
US5450274A (en) Spark gap arrangement
WO2012128729A1 (fr) Tube à décharge de gaz ayant un corps métallique pour des pointes de courant élevées
US10211603B2 (en) Surge protection element
US11025037B2 (en) Arrester for protection against overvoltages
CN110800177B (zh) 放电器
US4366523A (en) Arrester with spark gap
US9299527B2 (en) Gas discharge tubes for surcharge suppression
WO2014168589A1 (fr) Tube à décharge de gaz plat
US6559578B1 (en) Spark plug for an internal combustion engine
US1213844A (en) Protective device.
US10186843B2 (en) Spark gap arrangement
US10910795B2 (en) Arrester for surge protection
RU2719630C1 (ru) Коммутирующее устройство
TWI435371B (zh) 複合氣體放電管
US3665255A (en) Overvoltage arrester
GB1564224A (en) Excess voltage arresters
RU2328066C1 (ru) Разрядник грозозащитный

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12725554

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 12725554

Country of ref document: EP

Kind code of ref document: A1